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EIGRP over Fram Relay Issue

1. R5, R4, R1 are forming a FR hub and spoke topology R1 is hub. All three interface are physical.

2. IP-FR mappings are static. on hub there are two maps each for one spoke with keyword broadcast. On spokes there are two maps one pointing the hub with keyword broadcast, one pointing the ither spoke WITHOUT keyword broadcast.

3. Those three physical interfaces running on the same EIGRP AS.

When I check the EIGRP neighbors from the spokes I see both hub and other spoke as EIGRP neighbor. Isn't this strange. From a spoke when I trace the other spoke serial interface I see that I'm passing through the hub,this is normal. So how can an EIGRP neighborship is formed even though there's a layer3 hop between them and there's no static broadcasrt enabled frame relay mapping.

Regards.

3 REPLIES
Bronze

Re: EIGRP over Fram Relay Issue

This is weird. Do u have an additional dlci connecting R4-R5 directly?

Do a manual clear on the neigbor, do u still get the eigrp neighbor established from spoke-to-spoke?

On spokes, even if u've configured both frame-relay maps with broadcast keyword, out via the same dlci, u won't be able to establish neighbors with the other spoke. Since by nature, the hub's interface, will not forward the "multicast" packets from R4 out to R5. Configuring the 2nd frame map statement to reach the other spoke with broadcast keyword is merely sending redundant broadcast/multicast packets to your hub.

Re: EIGRP over Fram Relay Issue

If my understanding is right. I believe all the static mapping accomplishes is routing for layer2 the actual path is still using the main mapping.

Remember the hub side has no extra command lines it is still using the broadcast mappings.

When frame-relay inverse-arp is enabled, broadcast IP traffic will go out over the connection by default

I found this on link:

http://www.cisco.com/en/US/tech/tk713/tk237/technologies_tech_note09186a008014f8a7.shtml#topic2

Mike

Re: EIGRP over Fram Relay Issue

No inverse arp, only static mappings. We think the same.

Regards.

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